Circuit breaker



June 24, 1947. F. J. POKORNY CIRCUIT BREAKER Original Filed April 27, 1940 5 Sheets-Sheet l INVENTOR FRANK J POKORNY,

ATT'DRNEY.

1 o o H a k June 24, 1947. F. J. POKORNY CIRCUIT BREAKER Original Filed April 27, 1940 5 Sheets-Sheet 2 ATTORNEY.

June 24, 1947.

F. J. POKORNY CIRCUIT BREAKER Original Filed April 27, 1940 5 Sheets-Sheet 3 llll uulnnmm A INVENTOR FRANK J POKORNY,

ATTORNEY- June 24, 1947. J. PQKORNY 2,422,799

CIRCUIT BREAKER Original Filed April 27, 1940 5 Sheets-Sheet 4 FIG.9

{NVENTOR FRANK J POKORNY,

ATTORNEY June 24, 1 47. F. .J. POKORNY 2,422,799

CIRCUIT BREAKER Original Filed April 27, 1940 5 Sheets-Sheet 5 F'IGJG.

INVENTOR FRANK J POKORNY,

ATTOP NEY.

Patented June 24, 1947 CIRCUIT BREAKER Frank J. Pokorny, Philadelphia, Pa., assignmto I-T-E Circuit Breaker Company, Philadelphia, Pa., a corporation of Pennsylvania Original application April 27, 1940, Serial No. 331,984. Divided and Hill application April 27, 1943, Serial No. 484,891

This invention relates to switch gear and circuit breakers, and more particularly to a panel typ combination switch and circuit breaker adapted for use in branch circuits of various types and arranged to be mounted upon a panel board together with other similar devices for controlling a plurality of circuits.

In the operation of branch circuits, it is frequently important to connect or disconnect individual circuits from the main line without interfering with the operation of other similar circuits, and to arrange for overload protection for individual circuits so that in the event of any fault in any particular branch, that particular circuit may automatically be disconnected without interfering in any way with the operation of other circuits or with th operation of the main circuit itself.

Thus, in the operation of a plurality of small motors for various purposes in a shop, it is important that any fault occurring in the circuit to a particular motor should not affect the operation of other motors or the main line to the end that continuous operation should as far as possible be maintained.

Likewise, in the operation of multiple dwellings or apartment houses where a plurality of individual circuits for different apartments are all connected to a single main line, it is important that any particular circuit to any particular apartment be readily connectible to and disconnectible from the main line and that any fault in any particular circuit should not disturb the operation of any of the other circuits.

Accordingly, the purpose and object of the present invention is to provide a simple combination on-ofl. switch and circuit breaker which may be mounted upon a panel board and connected between the main bus and the individual branch circuits in order to provide suitable manual or automatic control for each of the individual circuits.

In order to provide for panel board mounting of this type and in order further to provide for simplicity in operation and assembly and to facilitate mounting upon the panel board, it is important that the particular combination switch and circuit breaker be compact and nevertheless so arranged as to obviate any internal faults or short circuits.

Therefore, instead of providing for the creation of a simple air-gap between the movable contact member and the stationary contact member of the on-off switch circuit breaker combination, one of the important objects of the present invention is to provide for the interposition of an actual physical dielectric barrier between the two contacts when the contacts separate.

Still another extremely important object of the present invention is to so arrange the stationary and movable contacts that they are separated not by any operation intially performed upon the movable contact itself, but by the sweeping or swinging of the physical barrier of dielectric matqrial toward circuit opening position. In such case, the barrier may swing beneath a bearing on the movable contact arm, raising the arm, and separating the contacts, and then the barrier by continuing the movement reaches its final .position between the separated contacts.

The movable contact should therefore be so arranged that it is biased into contacting position with the stationary contact in such manner that upon removal of the physical barrier of dielectric material the biasing means will immediately re-esiablish contact pressure between the movable and stationary contacts.

Still another object of the present invention is to provide for individual and separate physical barriers for each of the two operations of ordinary manual switching and automatic switching. That is, one barrier of dielectric material hereinafter referred to as an interposer may be placed between the contacts by manual operation and another such interposer may be interposed between the movable and stationary contacts by automatic circuit breaking means. Both of these barriers may operate in a single plane and it is still another object of the resent invention to utilize the manually operated inter-poser or barrier to remove the automatically operated interposer or barrier from between the contacts when it is desired to reset the switch and circuit breaker after an automatic tripping thereof.

The circuits and apparatus may be designed to carry (a) a maximum current above and below which small variation may occur (b) a heavy momentary inrush current as in thermal devices such as lamps where operating resistance increases after being switched on (0) starting currents for motors (d) short periods such as may occur in meters.

When these momentary increases occur, the length of time they last should be limited by the circuit breaker preferably in accordance with the square of the current and directly in accordance with the time (FT). Whenever the current exceeds the normal maximum value, then however, the circuit should be interrupted as quickly as possible.

It is an important object of the present invention to provide for independent means for automatically operating the circuit breaker in accordance with either of these conditions.

In the case of a short circuit where the resistance drops to zero or substantially zero, this invention provides for an instantaneous trip mechanism for immediately separating the contacts. Where a fault occurs however which is not sumcient to cause operation of the instantaneous trip mechanism, but is nevertheless such that excess heat may be generated in the'circuit, then a thermal means reponsive to increased heat in the circuit may be utilized for the p se of automatically separating the contacts in accordance with the aforementioned I T characteristic.

A further important object of the present invention is to mount the interposer which is automatically brought between the contacts by either of the means above-mentioned in such a manner that it is always biased toward contact separating position so that in the event of failure of the mechanism, the automatically operated interposer would be more likely to move to a position separating the contacts than to any other position.

A further object of this invention includes the mountin of the manually operated switch lever in such manner that it is yieldingly but positively held in the open circuit or closed circuit position.

Still another object of this invention is to so arrange the insulating housing of the circuit breaker that it may be readily molded by means of ordinary core dies without any other expensive molding or forming processes.

Still another and extremely important object of the present invention is the arrangement of the housing of the combination switch and circuit breaker, and the various parts thereof in suchmanner as readily to facilitate assembly. That is, the housing is so formed and each of the parts is so formed that the parts may readily successively be placed in the housing from one side, the assembly operation requiring merely a series of successive steps without any requirement for complicated tools or complicated supporting and holding means for combining and supporting the members during assembly.

A still further object of the present invention is to so arrange the housing and each of the parts that when the cover plate is secured to the housing at one side thereof, each of the parts is securely locked in operative position.

Many other objects and uses of the present invention will in part be apparent and in part pointed out in the following description and drawings, in which:

Figure 1 is an external view of the combination switch and circuit breaker.

Figure 2 is an elevational view showing a pinrality of the members of Figure 1 mounted upon a panel board.

Figure 3 is a cross-sectional view taken on line 33 of Figure 2.

Figure 4 is a side view of the circuit breaker of Figure 1 with the cover plate removed and with the contacts and various members arranged in open circuit position.

Figure 5 corresponds to the view of Figure 4 showing the contacts and various members in ordinary closed circuit position.

Figure 6 is a cross-sectional view taken on line 6-6 of Figure 4, looking in the direction of the arrows.

Figure 7 is a cross-sectional view taken on line 1-1 of Figure 4, looking in the direction of the arrows.

Figure 8 is a cross-sectional view taken on line 88 of Figures 6 and 7, showing the automatically operated interposer in latched position.

Figure 9 is a view corresponding to Figure 8. showing the automatically operated interposer in tripped position.

Figure 10 is a cross-sectional view taken on line Ill-l0 of Figure 4.

Figure 11 is a cross-sectional view taken on line |IH of Figure 10.

Figure 12 is a cross-sectional view taken on line l2-|2 of Figure 4.

Figure 13 is a cross-sectional view taken on line I3l3 of Figure 8.

Figure 14 is a cross-sectional view taken on line 14- of Figure 11.

Figure 15 is an exploded view of the combination switch and circuit breaker showing the manually operated interposer in circuit breaking position.

Figure 16 is an exploded view of the combination switch and circuit breaker showing the automatically operated interposer in circuit breaking position.

Referring now to Figure 1, I have here shown my combination switch and circuit breaker which comprises a principal housing 20 and a cover plate 2| secured thereto in any suitable manner, as for instance, by means of rivets 22.

The combination switch and circuit breaker comprises a manual operating handle 2'3 and circuit connecting means, separable contacts and automatic tripping means hereinafter more particularly described.

The combination switch and circuit breaker of Figure 1 is of a form and construction peculiarly adapting it for panel board operation for controlling a series of branch or subsidiary circuits fed from a main line or bus.' The arrangement of the members of Figure 1 upon the panel board as well as the arrangement of the various external portions of the switch and circuit breaker combination adapting it for use in panel boards will be more readily understood from a description of the interior construction and relationship of the parts of the circuit breaker itself.

The member of Figure 1 is shown in ordinary closed circuit position which, when the cover plate is removed, corresponds to the arrangement shown in Figure 5; while the arrangement shown in Figure 4 shows the position assumed by the parts when the manual operating handle 23 has been moved to open circuit position.

As will readily be seen from Figures 4 and 5, the combination switch and circuit breaker comprises a terminal or circuit connecting member 30 having any suitable means such as the threaded perforation 3| therein for connecting the circuit breaker to one terminal of the circuit. The current is led to the connecting lug 30 (which is preferably connected to the load) from the integrally associated conductive bar 32 which is connected, through the projecting lug 33 of the bar 32, to the bi-metallic element 3|.

The bi-metallic thermal element is at the bottom thereof connected to the flexible wire connection, preferably a copper braid 35 which is in turn conductively connected to the solenoid coil 31. The solenoid coil 31 is connected by means of the integral connecting bar 3| to the movable contact-carrying bar 3!, the said contact-carrying bar being preferably an integral extension of the bar 38.

The contact-carrying bar 39, as will be seen preferably in connectionwith Figure 13, carries the main movable contact block II. The current enters the movable contact block 40 at the movable contact surface II from the stationary contact surface II when the switch is closed. The stationary contact surface 42 is carried by the stationary contact supporting bar 42 (see Figures 13 and 16) which is in turn connected by the angular lead-in bar 44 (Figures 4 and 16) to the opposite terminal or lead 45, into which the current is led from the bus bar.

It will thus be seen that when the circuit breaker is so arranged that one terminal 30 thereof is connected through the load to one pole of the circuit and the opposite terminal ll (connected to the stationary contact) is connected to 'the opposite pole of the circuit, then the current a path is through the two contact surfaces ll and 42, and that any breaking of these contacts, that is, any separation thereof, will result in an opening of the circuit. Such separation of the contacts may be accomplished either manually, whenever it may be desired, or automatically in 'response to faults or over current conditions occurring in the circuit which the present circuit breaker is designed to protect. For the purpose of separating contact surfaces ll and 42 it may be sufllcient merely to move the movable contact a sufllcient distance away from a stationary contact so that the air or gases between them furnishes sufiicient dielectric interposition to prevent effectively the passage of current therebetween.

Where, owing to the fact that for panel board mounting of these circuit breakers, the various dimensions thereof must be compressed as far as possible and the amount of travel permissible in the movable contacts is relatively limited, then in order to effectively break the contacts apart so that no current may flow therebetween, the present invention relies not on a sufllcient movement of the movable contact to accomplish this purpose, but principally on the interposition of a physical barrier of dielectric material which either eifectively serves to lengthen any possible arcing path beyond the limits within which an arc may be maintained for the particular current and voltage rating of the circuit breaker or effectively serves to prevent any arcing path whatever.

Accordingly, for manually separating the contact when it is desired at selected intervals to disconnect the particular branch circuit controlled by the switch and circuit breaker combination, I prefer to utilize the manually operated interposer 50 (see particularly Figures 4, 5 and The manually operated interposer 50 is so arranged as seen in Figures 5 and 4, that it may be readily moved from the position shown in Figure 5 to the position shown in Figure 4, where it is interposed between the contacts as is even more particularly seen in Figure 12.

The manually operated interposer 50 is connected by rivets 5|, Si or in any other suitable manner to the foot 52 of the manual operating lever 23. The manual operating lever as is more particularly seen in Figures 4, 5 and 15, comprises a finger grasping portion 60, knurled to insure a firm grip, a foot 52 for supporting the barrier 60. and a central pivoting portion 6|. Preferably the manual grasping portions 60 and the central pivoting portion 6i as well as the foot 52 are integrally molded from insulating material as a single unit.

The interposer 50 securely attached to the foot 52 preferably is formed and pressed from a suitable insulating dielectric material to a thickness facilitating interposition between a movable and stationary contact. The central portion ii of the ma ual p ating arm 23 comprises. as is more particularly seen in Figure 4, a central opening or perforation 10 into which projects a knife edge ll, preferably integrally molded with the entire manual handle portion 22.

Owing to the fact that the handle 23 preferably is made of insulating material which may under appropriate circumstances possibly be brittle, the knife edge Ii is given a sufllciently wide base so that in ordinary operation it will be adequately supported for the purposes hereinafter described. The perforation 10 in the manual handle member 22 and the knif edge ll thereof cooperate to form a relatively frictionless playless bearing for the handle 23 when the perforation 10 thereof is mounted over the supporting post orspindle I2.

The supporting post or spindle 12 preferably is of insulating material integrally molded as a projection of a side of the main housing, although it may be formed of any other suitable material and attached in any appropriate manner to the main housing and comprises a cut-out portion 13 having adjacent surfaces forming an angle 14 between them (see Figures 5 and 16).

When the manual operating handle 22 is mounted upon the spindle 12 so that the knife edge ll thereof registers with the angle 14 of the spindle and so that the perforation 10 of the central portion it of the manual operating member cooperates with the remainder of the spindle 12, then the manual operating handle 23 may readily be rotated about the spindle within definite limits or stops. That is, the manual operating handle may be rotated from the .position shown in Figure 5 to the position shown in Figure 4, in each case the side of the knife edge approaching one of the surfaces of the cut-out 13 of the spindle.

During the actual rotation, the principal bearing surface between the manual operating handle and the spindle is the knife edge II of the manual operating handle pressing into the angle 14 of the spindle. Thus, even though the perforation 10 of the manual operating handle is slightly larger in diameter than the greatest diameter of the spindle, nevertheless the pressure of the knife edge H of the handle into the angle 14 of the spindle furnishes an eflicient, play-less bearing.

The bearing herein is described as a playless one simply because it is not a point-to-point contact between a point and an angle but a knife edge contact over an appreciable length with a corresponding angular member; and such a knife edge contact over such appreciable length prevents any wobble or torque of such nature as to twist the handle out of a plane perpendicular to the axis of the spindle.

The finger grasping portion 60 of the manual operating handle 23 projects through the slot in the upper surface 81 of the housing. The movement of the manual operating handle 23 from the closed circuit position shown in Figure 5 to the open circuit position shown in Figure 4 is effectively limited by the shoulders 82 and 83 which lie at either end of the slot 80 and serve effectively to prevent further movement of the manual operating handle 23.

The manual operating handle 23 is so arranged that it is yieldingly biased either in open circuit position when it is left in that position or into closed circuit position when it is left in closed circuit position. That is, a, spring is so arranged relative to the center of rotation of the manual operating lever that when the manual operatin lever is moved either toward closed or open circuit position, the spring .passes beyond center and serves yieldingly to lock the manual operating lever in place.

The compression spring 90 (Figures 4, and 15) which accomplishes this function is mounted upon a slidable steel bar 9i which terminates at one end thereof in a yoke or bearing surface 92. The opposite end of the bar at 93 projects through a perforation 84 in a suitable bearing plate 95, preferably of insulating material. The slidable steel bar is so arranged that the end 93 thereof may slide freely in the perforation 94 of the bearing plate 95. The yoke or bearing surface 92 of the steel bar 9| engages a notch 96 in the peripheral surface of the central portion 6| of the manual operating arm 23.

The spring 90 is maintained under compression between the bearing plate 95 and the flanges of the yoke or bearing end of the steel bar 92. As may readily be seen in Figure 5, when the manual operating arm 23 is rotated into position where the interposer is not between the contacts and hence when the circuit breaker is in closed circuit position, then the effective pressure exerted by the compression spring 90 between the bearing plate 95 and the notch 96 is so directed beyond the center of rotation of the manual operating lever 23 (the knife edge H and angle 14 engagement) as to exert a torque upon the manual operating lever 23 tending to drive it even further in such direction as to swing the interposer 50 away from the contacts and to swing the finger grasping portion 60 thereof up against the stop 83.

When the manual operating lever 23 is rotated from the position shown in Figure 5 to the open circuit position shown in Figure 4 and the interposer 50 is interposed between the contacts to produce the open circuit position, then as will be noted by a comparison of Figures 4 and 5, the notch 96 of the central portion SI of the manual operating lever 23 has been rotated to such position that the effective force generated by the compression spring 90 is directed beyond the center of rotation of the manual operating lever in an opposite direction from that in which it was directed in the closed circuit position of Figure 5, thus tending to drive the finger grasping portion 60 of the manual operating arm 23 against the stop 82 and tending further to drive interposer 50 into open circuit position.

Obviously, the reason that the compressive force of the spring 90 is either in the open or in the closed position exerted in such direction as to maintain the particular position of the switch (whether open or closed) is that the axis of the spring is in each case shifted beyond the center of rotation so that the effective direction of the force exerted by the spring changes from the counterclockwise direction with respect to Figure 5 to a clockwise rotation with respect to Figure 4 about the center of rotation.

As will be noted from a comparison of Figures 4 and 5, the spring 90 is in a position under greater compression and much less beyond center when the switch is in the open circuit position of Figure 4 than when the switch is in the closed circuit position of Figure 5.

Accordingly, a positive closing action is provided for the closing of the switch, that is, it requires only a slight movement of the finger grasping portion 60 of the manual operating lever 23 (when the circuit breaker is in the position shown in Figure 4) to move the manual operating lever 23 so that the force exerted by the spring passes through center and is exerted in an opposite sense to snap the manual operating arm 23 into closed circuit position.

Thus, when the switch is in open circuit position, it requires merely flicking of the finger grasping portion 60 of the manual operating lever 23 to cause the interposer 50 to be snapped out of its position between the movable and stationary contact. Also for this reason, the possibility that the contacts might remain in bare proximity to each other without actual complete removal of the interposer 50 is greatly minimized since in the circuit opening position it is necessary for the circuit opening movement to be substantially completed manually or else the manual operating lever 23 and the finger grasping portion 60 thereof will immediately snap back to circuit closing position.

The position of the finger grasping porton 60 of the manual operating lever 23 generally will indicate the on or off condition of the switch unless the switch or circuit breaker has been automatically tripped open in which case other indicating means hereinafter described may be utilized.

In order that, upon the removal of the barrier 50, from the position shown in Figure 4, where it is between the movable and stationary contacts to the position shown in Figure 5 where it is no longer between these contacts, the movable contact should come into closed current conducting contact with the stationary contact, I provide a leaf spring I00 (Figures 4, 5 and 16) which tends to drive the movable contact surface 4| (see also Figure 13) down upon the stationary contact surface 42. The leaf spring I00 preferably is mounted upon a surface I0! of the housing and secured thereto by a washer I02 and one of the rivets 22a which serves to secure the cover plate 2| to the housing. In order to insure that the leaf spring will be accurately positioned to exert proper contact pressure upon the movable contact, I provide a lug I03 extending from the leaf spring and registerable with a recess I04 of the housing which registry will serve adequately to prevent undue rotation of the leaf spring around the rivet 22a.

The leaf spring I00 preferably is formed of any suitable elastic metal preferably of spring steel and is so arranged and bent as seen particularly in the perspective exploded view of Figure 16 as to exert pressure upon the contact-carrying arm 39 in such direction as to bias the contact block 40 and the movable contact surface ll thereof into engagement with the stationary contact surface 42.

In order further to ensure that the movable contact-carrying arm 39 cannot escape the pressure, I prefer to shear the end H0 of the leaf spring I00 in such manner as to provide a pressure transmitting surface Ill thereon which presses down upon the contact bar and to provide guide flanges H2 and H3, the edges of which engage the sides of the contact-carrying bar 39, and prevent the escape of the contactcarrying bar from the leaf spring and vice versa.

Obviously, a great deal of friction would be generated by the movement of the barrier 50 between the surfaces ll and 42 of the contacts unless some friction reducing means were provided. Such friction reducing means, however, must be of such a nature as not in any way to interfere with the effective pressure between the 7 two contacts when the circuit is to be closed,

while it must be readily usable to reduce the friction caused by the passage of the interposer 50 during the movement of the interposer 50 between the contacts.

Accordingly, a wheel I20 made of suitable insulating material is loosely mounted as is more particularly seen in Figures and 13 upon a rivet I2I is in turn mounted on the perforation I22 of the movable contact block 40.

The stationary contact surface 42 projects somewhat as will be seen in Figure 13, above the main portion of the stationary contact-carrying bar 43. In order to protect the Bakelite housing from the effects of any momentary arcing that may occur during the instant of breaking of the contacts, an insulating plate of any suitable material i (see particularly Figures 8 and 13) is placed upon the inner side of the housing and over the stationary contact supporting members.

The insulating plate I30 has a perforation I3I therein which registers with the stationary contact surface 42. The insulating plate also has a perforation I32 therein which provides a recess into which the wheel I20 may descend so that adequate pressure may be maintained between the contact surfaces 4I and 42. In order further to protect the housing 20 at I from any arcing that might occurduring the instant of opening of the circuit, an additional small plate I36 of insulating material is placed beneath the perforation I32 effectively to protect the housing from any stray arcs that might momentarily exist.

When the contacts are in closed circuit position, it will thus be noted by reference to Figure 13, that the contact surfaces 4I and 42 may come into close positive abutment in relation to each other owing to the fact that the recess I32 in the bas insulating plate I30 permits the wheel I20 to descend beneath the surface of the contact without creating any back pressure tending to separate the contacts or tending to raise the movable contact away from the stationary contact. Further. since after a period of use, the contacts may wear, the contact supporting members must be capable of movement closer together. The depth of the recess is such as to provide allowance for this additional movement during the life of the breaker. The prime purpose of the wheelis to prevent friction between the interposer and the contact surface.

When the interposer 50 slides between the contacts it, however, as will clearly be seen by a comparison of Figures 4 and 5 with Figure 12, first comes into contact with the freely rotatable wheel I20. Since the wheel is freely rotatable the barrier may readily slide thereunder an owing to the fact that the barrier is arranged so as to be unyieldingly mounted in its own plane, then the continued sliding of the interposer 50 owing to manual or other pressure, will cause a raising of the wheel I20 and a consequent raising of the movable contact block and of the movable contact surface 4I, thus permitting the interposer to slide between the contacts.

In order to facilitate this, the interposer 50 may be bevelled at the leading edge thereof which first comes into contact with the wheel I20 in order to facilitate the raising of the wheel. However, ordinarily the interposer 50, although it is of sufficient thickness to provide for a sufllcient dielectric barrier between the contacts when it is in open circuit position and although it is of sufllcient strength to permit it to separate the contacts by the means herein described, it is 10 nevertheless sufliciently thin so as to not make any such bevelling essential for the purpose of lifting the movable contact wheel.

By this means, therefore, the contacts may be manually opened or closed from the outside of the housing by merely applying finger pressure in the proper direction to the finger portion 00 of the manual operating lever 23.

In the event of sudden overloads of great intensity or in the event of a sudden large drop in resistance, it becomes important immediately and automatically to open the circuit, that is. to separate the movable and stationary contacts. Likewise, also, in the event of an overload of less intensity or a drop in resistance below normal and sufficiently to permit the passage of current to such an extent as to cause over-heating, means are provided in the present device for also separating the movable and. stationary contacts and thereby opening the circuit at that point.

Both of such means, that is, the means responsive to sudden increased overloads and the means responsive to milder overloads which eventually may be deleterious, are so arranged as to actuate the automatically interposable barrier or interposer I 50 (see particularly Figures 8 and 9 as well as Figures 15, 4 and 5). The automatically interposable interposer I50 comprises, in addition to the interposing portion thereof which is preferably made of substantially the same dielectric material as the interposer 50, a central portion I5I and a latch engaging arm I52.

The central or mounting portion I5I of the automatically interposable interposer I50 is as is most clearly seen in Figures 8 and 15, perforated at I53 to permit the mounting of the interposer I50 upon the spindle I2.

The spindle I2 has an increased diameter at I54 which is the base portion thereof, most closely adjacent to the wall of the housing. The cut-out portion I3 of the spindle I2 nevertheless extends into this larger portion of the spindle and the angle I4 formed between the surfaces of the cutout portion also extends into the enlarged portion of the spindle. The enlargement of the spindle 12 at I 54 permits not only for a more secure connection between the spindle and the wall on which it is mounted but also serves to register and align the various members upon the spindle. That is, the perforation I53 of the automatically interposable member I50 is of a size permitting accurate registry of the perforation I53 with the large portion of the spindle I54, while the perforation III of the manual operating lever 23 is of a size registering with the narrower portion of the spindle I2.

Thus after the automatically interposable member I50 has been placed upon the wider portion of the spindle I54, the manual operating lever may be placed thereon and by reason of the fact that the side thereof abuts against the surface portion I50 of the wider portion I54 of the spindle, the manual operating lever cannot in any way interfere with the operation of the automatically interposable interposer I50. This is more particularly so since the mounting portion I5| of the automatically interposable membcr I50 is slightly narrower than the length of the wider portion I54 of the spindle 12 so that the mounting I5I may be free of contact with the central mounting portion SI of the manual operating lever 23.

The interposable barrier I50 is so arranged that it may be readily rotated about the portion I54 of the spindle. For this purpose, an angular projection llil is integrally extended from the body of the mounting section |l of the interposable member I50 into the perforation I53. The angular projection I5I registers with the angle ll in the spindle and provides a suitable bearing for the rotation of the automatically lnterposable barrier I50.

Rotation of the automatically interposable member I50 about the spindle is also limited by the spacing of the walls of the spindle which surrounds the angular portion ll thereof. That is, as seen in Figures 8 and 9, a positive stop is provided in each direction of movement of the interposer I50 :by the abutment of the sides of the angular portion IF I against the walls of the spindle which join to form the angle ll thereof.

A compression spring I10 (Figure 8) is mounted on a steel slide bar Ill. The steel slide bar has a yoke or bearing surface I12 which at one end thereof bears against a notch I13 of the automatically interposaible interposer I50. At the opposite end of the slide bar, the bar is at I14 inserted in a perforation l'l5 of an insulating bearing plate I15. The end I14 may slide freely in the perforation I15.

Compression spring I10 is under compression between the bearing plate I15 and the flanges of the end bearing I12 of the steel slide bar Ill. As may be noted especially in connection with Figure 8, even when the automatically interposable barrier I50 is not between the contacts, the axis of the compression spring I" is so arranged that the force exerted thereon is to the left of the center of rotation at iii and hence is so directed as to cause the interposer I50 to rotate in a counterclockwise direction with respect to Figure 8.

The interposer I50 is restrained from counterclockwise movement in response to the action of compression spring I10 by the latch engaging arm I52 thereof. The latch engaging arm I52 carries secured thereto by rivets or any other suitable fastening means, a steel bearing plate I00 which engages the latch ill of the trigger I02. Upon movement of the trigger I02 in such a direction as to release the engagement between the metal bearing I80 and the latch l0l there is no further restraint upon the rotation of the barrier I50 and since the action of the compression spring I10 is such as to immediately initiate counterclockwise movement thereof with respect to Figure 8, then immediately upon such disengagement, the compression spring I10 will force the interposer I50 into the position shown in Figure 9 where it extends between the movable and stationary contacts.

The open circuit position of the barrier I50 is definitely fixed by the abutment thereof against the edge of the handle shutter 50 which thus halts continued rotation of the interposer I50 in response to the action of the spring I10.

By proper arrangement and spacing of the shutters (that is the closed circuit non-interposing position of the shutter 50 and the open circuit interposing position of shutter I50) it is possible to ensure that in the tripped position of the circuit breaker, the interposer I50 will be positioned as shown in Figure 9 directly between the movable and stationary contacts.

The abutment of the edges of the shutters in the tripped position forms a complete continuous seal between the contacts cutting off any possible effective are path. Thus it may be seen by a comparison of Figures 8 and 9 with Figures 4 and 5, that when the manually operated interposer 50 is in the closed circuit position of Figare 5, a free path is provided for the descent of the automatically operated interposer I50 so that it may readily move from the position shown in Figure 8 to the position shown in Figure 9 immediately upon release of the latch III of the trigger I02 from its engagement with the metallic bearing surface I00 of the latch engaging portion In of the interposer m.

Therefore when by the operation of the manual operating lever 23, the barrier 50 is moved to closed circuit position, that is, to a position where it no longer extends between the movable contact and the stationary contact, no impediment of any kind exists to the automatic interposition of the interposer I50 between these contacts in response to a release of the latch engaging portion thereof I50 by the trigger I02.

Normally when no fault conditions exist upon a line, the trigger I02 is so arranged that the latch portion IOI thereof engages the bearing plate I00 of the interposer I50. For the purpose of retaining the interposer in the desired non-interposing position, the trigger I02 is spring biased by means of spring 200 (Figures 10 and 11) into latching position,

The trigger I02 has a central mounting portion "I which is perforated at 202. An integral projection of the material of the trigger 20! extends into the perforation 202 and terminates in a pointed angular portion 204 which provides a bearing for the trigger upon its shaft, permitting rotation thereof upon the shaft within predetermined limits. The mounting of the trigger, as is seen in Figures 10, 11 and 14 comprises a spindle 2l0 preferably integrally formed from and secured to the wall of the housing and having a notch 2II therein.

The angular point 204 of the trigger projects into the notch 2 which thus provides an angular bearing surface. The trigger I02 may thus rotate within predetermined limits on the spindle 2I0 (Figure 14). A sleeve 2I2 is mounted on the spindle 2I0 and between the side of the trigger and the side of the cover plate, thus accurately positioning the trigger upon the spindle. A hole in the spindle 2I0 at 2I3 (Figure 10) permits one end of the spring 200 to enter therethrough and engage a wall of the groove or notch 2; the spring is wound about the sleeve, the other end at 2I6 engaging the trigger I02.

The spring is so arranged that it exerts a rotative force upon the trigger about the spindle 2I0 in a counterclockwise direction with respect to Figure 9 and hence tends to bias the trigger I02 so that the latch portion IOI thereof is positively in engagement with the metallic bearing I00 of the latch engaging portion I52 of the interposer I50.

Any fault condition existing upon the line must be manifested in some mechanical way which may be utilized to cause a rotation of the trigger in such a direction as to release the latch engaging portion I52 of the interposer from the latch III of the trigger. Accordingly, arms 220 and HI are provided on the trigger to cooperate with elements which respond mechanically to variations in the amount of current.

Trigger release arm 220 is so arranged as to cooperate with the member 205 of the solenoid assembly 230 in the manner shown in Figures 4, 5, 8 and 9. As has been above noted, the solenoid is in the current path through the movable and stationary contacts. Thus, with respect to Figure 4, the current enters at the connecting lug or terminal 05, passes through the contact blocks and the members 39 and 30 into the coils 31 of the solenoid and thence through the wire braid 35, the thermal element 34 and the lug 33 and bar 32 into the opposite terminal 30.

The solenoid coil 31 is composed of several turns of conducting material which, in the preferred embodiment of the present invention, is

- square copper of substantial cross-section. The

large cross-sectional area minimizes the resistance which is injectedinto the circuit and also increases the actual physical strength of the coil, thus making it possible to use an integral extension 38-39 of the solenoid coil itself as the lead-in and physical support for the movable contact block.

It will be noted that the contact engaging spring I forces the contact member 40 toward the molded wall of the housing. The point of engagement of this spring with the bar 39 is between the contact and the coil. The spring thus produces reactions at each end of the bar 38-39; one, producing contact engaging pressure when the interposers are retracted; the other maintaining the solenoid assembly in its sockets.

To obviate the necessity for insulation on the solenoid, the coil preferably is wound with a reasonably large air space between the turns. The solenoid coil 31 as is seen in Figures 4, 5, 8 and 9 is mounted on an insulating sleeve 25 which prevents any current leakage between the successive turns of the coil and at the same time serves to insulate the coil from other members of the mechanism.

The insulating sleeve 23I may be secured within the housing in any suitable manner. Thus one end thereof may at 232 be supported in a depression of the bottom wall of the housing and the opposite end thereof may be supported in a U-shaped member 233 preferably integrally molded from a wall of the housing.

For purposes of securing the support of the sleeve 23I at 232 in the housing, a steel core 234 having a flange 235 engaging the sleeve may be secured at the bottom of the sleeve to provide a suitable bearing for the main armature spring and further to rigidify and strengthen the sleeve against any stresses that may be placed thereon. The movable solenoid armature 240 is slidably mounted in the top of the sleeve 23I and preferably may be maintained in the normal raised position shown in Figure 8 by the compression spring 24I which is placed between the base of the movable armature and the top of the stationary core. Since the slidable armature 240 is preferably made of steel or any other suitable magnetizable material, it may be drawn down so that it extends substantially within the coils 31 of the solenoid when a sufiicient current is passed through such coils.

Spring 2 of the solenoid should be so callbrated and arranged that it will permit the drawing of the armature 240 within the coils of the solenoid in response only to an overload sufficiently excessive to possibly cause damage. That is, the spring I should not permit descent of the solenoid armature 240 when ordinary currents customarily to be expected in the circuit are passing through the coil 31. Nor should it even permit descent of the armature when only slightly excessive currents are passing through the coil. But the movement of the armature 240 into the coil should be in response only to excessive loads.

The circular cross-section of the armature 240 and the free fit thereof within the sleeve 23I permits it to slidev readily. A rectangular trigger arm engaging member 245 is secured either by welding or by any other suitable means to the top of the armature. Preferably as is seen in Figure 15, the trigger arm engaging member 245 is squaredoff and preferably the interior wall 245 (Figure 9) is close to the plate 245 of the armature (see also Figure 6).

As is therefore seen particularly in Figure 6, while the squaring-off of the plate 245 does not interfere with the rise or fall of the armature, it prevents undue rotation of the armature to ensure that the trigger arm engaging portion there- 'of will always extend in such a direction as to engage the trigger and to ensure that it will not rotate out of engagement with the trigger.

The slots 241 (Figure 15), cut into the armature 240 and magnet 234 and the slot 248 out into the trigger arm engaging plate 245, serve to prevent eddy currents which might otherwise tend to reduce the total magnetic flux in the cir cult or occasion any loss of energy owing to heating.

When an overload occurs for any reason causing an excessive current to pass through the coil 31 of the solenoid, then the armature 240 is attracted into the coil of the solenoid, the plate 245 engages the trigger arm 220, presses the arm downwardly with respect to Figure 9, causes a rotation of the trigger about the spindle 2i 0 in a direction opposite to that in which the trigger was originally biased by the trigger spring 200, causes a movement of the latch portion I8I thereof out of engagement with the bearing I of the latch engaging arm I52 of the interposer I50 and thus removes any restraint upon the rotation of the interposer I50, thereby permitting the compression spring I10 to drive the interposer to the position shown in Figure 9, where the interposer I50 as will now be clearly understood, extends between the movable and stationary contacts.

Obviously, any such tripping of the interposer I50 into circuit opening position shown in Figure 9 will not occur owing to the energization of the solenoid 230 unless the movable and stationary contacts are pressed together, that is, unless the entire mechanism has first been placed in the position shown in Figure 5 where the manually operated interposer 50 is no longer between them.

As will be noted in Figure 5, when the manually operated interposer 50 is moved from the open circuit position of Figure 4 to the closed circuit position of Figure 5 then not only does it permit the circuit to be closed between the movable and stationary contacts but also it is moved to a position where it will not interfere withthe descent of the automatically operated interposer upon release of its latch engaging arm I52. So that when the automatically operated interposer I 50 moves from the position shown in Figures 5 and 8 into the position shown in Figure 9, in response to over current conditions. it is clearly free to do so without interfering with the interposer 50.

Obviously when the interposer I50 moves from the position shown in Figures 5 and 8 to the position shown in Figure 9, it engages and raises the wheel I20 and separates the stationary and movable contacts in exactly the same manner as has been shown heretofore in the manually operated interposer 50. The manually operated interposer 50 is off -set out of the principal plane of the main portion of the manual operating lever 23 so that it will be coplanar with the automatically operated interposer I 50.

This condition simplifies the resetting process after the automatically operated interposer I50 is tripped.

Obviously once the automatically operated interposer I50 is tripped to separate the contacts, then the solenoid coil 31 is no longer energized and the spring 2 is free to restore the armature 240 to the original position shown in Figure 8.

There is therefore no restraining force upon the trigger arm 220 and the spring 200 of the trigger I82 is then free to restore the trigger to its original position preparatory to latching engagement with the arm I52 of the interposer I50. Since the interposer 50 and the interposer I50 are coplanar with respect to each other, it will be then clear that the movement of the manual operating lever 23 from the closed circuit position shown in Figure 5 to the open circuit position shown in Figure 4 will result in a corresponding movement of the interposer 50 as shown and will also therefore result in the pushing up of the interposer I50 by the interposer 50.

When the manually operated interposer 50 has been moved into position shown in Figure 4, it will have raised the automatically operated interposer I50 so that the latch engaging arm I52 will be in latching engagement with the latch I8I of the trigger I82. And the circuit breaker will have been restored to its original non-tripped position but the circuit will then remain open since in the very operation of resetting the interposer I50, the interposer 50 has been moved into position between the contacts.

Subsequent to this operation which thus results in the position of the members shown in Figure 4, in order to restore the circuit, the manually operable interposer 50 must be moved back to the position shown in Figure 5. If, during such movement, and at the moment the movable contact touches the stationary contact, over current conditions still exist on the line, then the solenoid coil 31 will be immediately energized to trip the automatically interposable barrier I50 to tripped position. 1

It is thus absolutely impossible to hold the circuit closed when over current conditions exist on the line and to this extent at least the present invention is a trip-free circuit breaker. In other words, the tripping action which results in the placement of the interposer I50 between the movable and stationary contacts occurs independently of the manual operated lever 23.

The spring 200 which biases the trigger I02 in tripped in response to a specific excessive overload of substantial extent. It may be necessary or desirable to eflfect a similar tripping operation of the interposer I" when an overload which is not greatly excessive but is nevertheless continuous occurs.

In order to accomplish this purpose, I provide a thermal bi-metalllc element I0 (Figures 4, 5, 8 and 9) which is responsive to heating effects which may occur in this circuit. The thermal bimetallic element 04 is so arranged that the lower end thereof will be rotated clockwise with respect to Figure 8 under the influence of heat. The current path from the connecting lug 40 through the contacts and to the connecting lug II is through the thermal element 00. Thus the current is led from connecting lug 45 through the will be necessary not merely to calibrate the spring 2 of the solenoid in accordance with the particular overload current conditions which are to be expected but also to calibrate the spring 200 in accordance therewith.

It will also be possible, should it be desirable, merely to depend on the spring 200 of the trigger and to arrange this sprin so that it will permit a release of the latch only when a sufficient force is exerted upon the armature to rotate the trigger despite the force of the spring. In such latter case, spring 24I will not be necessary.

I have here shown, however, the preferred embodiment wherein compression spring 2 which may readily be calibrated is utilized to resist the force exerted upon the armature by the passage of current through the solenoid. By this means, the automatically operated interposer I may be bar 44 to the contact surfaces 42 and I, the contact supporting arms 20 and 38, the solenoid coil 31, the wire braid 35 to the thermal element; from the thermal element, the current flows into the thermal element supporting arm 32, thence through the bar 32 to the opposite connecting terminal 30.

Any overload conditions on the line which may result in the passage of sufllcient current to generate heat in the circuit but which may not be of suflicient intensity to energize the solenoid 230 may nevertheless be sufiicient to cause a bending of the thermal element 84. The thermal element 34 preferably is so calibrated that it will bend into engagement with the arm 22I of the trigger under predetermined excessive load conditions which are not greatly in excess of the desired current condition but which nevertheless result in the generation of excessive heat.

Upon bending of the thermal element 24 in response to such heating conditions in the circuit, the end thereof will be swung over in the manner shown in the dotted lines of Figure 5 into mechanical contact with the trigger arm 22I and'will cause a rotation of the trigger I02 about the spindle 2 I 0, such rotation releasing the latch portion IOI thereof from the metallic bearing II. of the latch engaging arm I52 of the automatically interposable interposer I50.

This permits a tripping operation to occur and permits the compression spring I10 to force the automatically operated interposer I50 into the position shown in Figure 9.

The automatically operated interposer may then be reset in the manner above described by the operation of the manual operating lever 23, but the trigger I02 will not be rotated to latching position by its spring 200 until the heating conditions which resulted in a curling of the thermal element 34 have been removed.

Thus, should the interposer I50 be reset in the manner above described immediately after tripping in response to heating conditions, it will immediately trip once more owing to the fact that the thermal element will not have had an op portunity to cool oi! sufliciently to permit it to disengage the trigger arm 22I. For this reason, therefore, the interposer I50 cannot be reset until whatever heat has already been generated in the circuit has had an opportunity to radiate away. If, after such radiation has occurred, the interposable barrier I50 should be reset and an excessive overload occur, the solenoid operating mechanism 230 will cause another tripping; and should there be in the case of such resetting a slight overload resulting in the generation of heat once more, then after heat has been generated for a suiliclent amount of time to permit the curling over of the thermal element 34, the interposer I50 will again be tripped and the circuit broken.

In every case it must be understood that the operation of the interposer I50 is completely free of the manual operating arm 23 and that it is absolutely impossible to maintain the circuit in closed circuit position when fault conditions exist upon the line.

The circuit breaker may be adjusted for different types of excessive overloads by proper calibration, and interchanging of the spring 2, and it may be adjusted for dlfierent responses to slight or heating overloads by either a change in the bi-metallic element or a shifting oi the bi-metallic element 34 with respect to the trigger arm 22I so as to require a difference in the amount of bending of the thermal element before it is in mechanical contact with the trigger arm 22I.

In order to provide for such shifting of position I provide that a screw 210 be threaded through the arm 33 which supports the thermal element 34 and that the end of this screw bear against the ledge 21I in the interior of the housing. The arm 33 is made of resilient conductive material and is sufliciently elastic so that upon rotation of the screw 210 the arm 33 will be moved closer to or further away from the ledge 2' thus changing the position of the mounting oi the thermal element 34 and shifting it closer to or further away from the trigger arm 22I.

The mounting portion SI of the manual operating lever 23 is so arranged that whatever the position of the manual operating lever, whether on or oil, the slot 80 is completely covered over so that virtually no dust may enter from the outside into the mechanism.

This results, however, in making it either difllcult or impossible to examine the interior of the mechanism while the circuit breaker is mounted upon the panel board to determine whether the circuit breaker has been tripped. As a matter of fact, even though the finger grasping portion 60 of the manually operated lever 23 is in the closed circuit position shown in Figure 5, the circuit breaker may be tripped open by the dropping of the interposer I50 to the position shown in Figure 9 without changing the position of the finger grasping portion 50. Thus unless some outward visual indication is provided as to the position of-the interposer I50, it will be diflicult if not impossible to determine whether a circuit breaker has been tripped.

Accordingly, I have provided a visual indicator which will readily show the position of the automatically operated interposer I50. The visual indicator is preferably a fiat metallic member 300 (Figures and 16) carrying a flag 30I and having a perforation 302 registerable with the mounting shaft I2 and an angular projection 303 registerable with the angle I4 of the mounting shaft. The indicator 300 is mounted upon the shaft 12 above the interposer I50 and the mounting portion SI of the manually operated lever 23. The indicator disk 300 also has a finger 305 preferably at right angles to the main portion of the disk 300 and extending as is shown in Figure 9 immediately below the latch engaging arm I52 of the interposer I50.

A spring 305 (Figure 9) is at one end thereof engaged in an opening 301 of the automatically operated interposer I50 and at the other end at 300 is caught beneath the finger 305. The central coil portion thereof is wound about the shaft I2 and is placed between the automatic inter- 18 poser I50.and the manual operating arm mounting II,

The spring 305 and especially the end 303 thereof is therefore biased to raise the ringer 305 and thus is biased in such a direction as to cause a rotation of the disk 300 so as to raise the flag 30I. Normally, however, when the automatically operated interposer I50 is in the latched position shown in Figure 8, the latch engaging arm I52 thereof presses down the finger 305 against the bias of the end 303 of the spring and hence also presses down the flag 30I so that it is not visible. When the automatically operated interposer I50 is tripped into the position shown in Figure 9 and the latch engaging portion I52 thereof is raised, then the end 300 of the spring pushes up the finger 305 of the indicator and pushes the flag 30I up into the slot 00 where it may be visible from the outside alongside the mounting portion SI of the manual operating lever 23.

Accordingly, even though the finger grasping portion 60 of the manual operating lever 23 is in the apparent closed circuit position, the appearance of the flag 30I in the slot 00 alongside the mounting portion 5| of the manual operating lever will immediately give an indication that the circuit breaker hasbeen tripped to open circuit position.

In order to provide a recess in the mounting portion ii to permit the flag 30I to appear in the slot 80, the mounting portion Si is cut-out at 3I0 to a depth sufficient to permit the entry of the flag 30I therein (3|0, Figure 5).

In order to prevent any possibility during the opening of the contacts of any arcing over between the movable contact block 40 and the bar 44, insulating barriers 320 and 32I (Figure 5) are provided mounted in notch 322 of the ledge or boss 323 in the bottom wall of the housing and in notches 324 and 325 of an end wall of the housing, the said notches being integral with the housing.

In order further to protect the members against arcing, an upper shield 340 is provided (see Figure 2) having openings 3 therein to permit the engagement of the contacts and the passage of the wheel therethrough. This protective shield may be formed or stamped to shape, the shape being, of course, determined by the contour of the housing and obviously this shield 340 is spaced from the bottom shield I30 by a distance suflicient to permit the free passage of the insulating interposers between them.

From the foregoing description it will be seen that each of the members of the circuit breaker is supported within the housing in such a manner that they may readily be assembled in connection therewith. The housing itself is so formed and constructed as to provide supporting elements of various types, most of which having hereinbefore been described. Thus, for instance, the bar 32 whichis an extension of the connecting lug 30 is securely mounted within the housing assembly by the screw 350 (Figures 4 and 5) which passes through a lug 35I of the bar 32 and into an integrally molded rectangular support 353 of the housing. The bar 32 is also securely positioned within the housing by being mounted between the rectangular abutment 363 and the angular portion 354 of the housing.

Each of the interposers and the manual operating lever rotates about a single spindle which is integrally molded from or secured to one wall of the housing.

tional view of Figure 6. Thus, the final securement of all of the members is obtained after most of the members have merely been slipped into place by the attachment of the cover member 2| and the passing of the rivets 22 through the elements and the housing.

Obviously, suitable on-off indication may be printed or written on the outside of the housing in cooperation with the manual operating lever 23 and particularly the finger grasping portion 60. If so desired the mounted portion ii of the manual operating lever may be lettered with the legend oil at 310 (Figures 4, 15 and 16) and with the legend on" at 31l (Figures and 16). Furthermore, the indentation 312 of the mounted portion SI of the manual operating lever 23 may be provided and may be suitably colored to indicate the on" position, since it will be visible only when the finger grasping portion of the manual operating lever 23 has been moved to the on position,

From the foregoing description of the various elements and the manner in which they operate, it will be clear that the same type of apparatus may be adapted, where desired, to multi-pole operation and where desired, it may be possible to place two or more of the combination switch and circuit breakers side by side for muiti-pole operation connecting the manual operating levers 23 by passing any suitable member through the perforation 380 (Figure 4) of adjoining manual operating levers so that multi-pole switching may be effected.

As has been above emphasized, while this circult breaker is useful for individual operation, the greatest utility lies in its arrangement and adaptability for panel board mounting in the manner shown in Figure 2.

The lead connecting lug 33, as will be noted particularly with reference to Figure 4, is protected by the curved extension 390 of the housing and may be enclosed between the cover plate and this extension. The lead 45 may, if desired, extend from the opposite side or it may where necessary be protected in asimilar manner by the extension 385 of the cover plate (Figure 1) and/or by a corresponding extension of the housing. For ordinary panel board mounting where the lead 45 is to be used as part of the support for the circuit breaker upon the bus it may be desirable to use a cover plate which terminates at the side of the housing. For this purpose a weakening line 296 comprising indentations or grooves or any other suitable weakening elements may be provided in the cover 2i to facilitate the breaking off of the extension 395 so that the circuit breaker may readily be mounted in the panel board shown in Figure 2.

In Figures 2 and 3 a plurality of circuit breakers of the present invention are shown mounted upon a panel board with the leads I! connected by suitable conductive securing means, as for instance the screws 391, to a common bus 392, and the opposite leads connected to load wires 39! in any suitable manner. The leads 4| obviously may be sufiicient to provide adequate support for one end of the circuit breaker upon the common'bus 393, although if desired any other securing means may be provided for this purpose, as for instance, the foot or lug I which may serve to engage a suitable clamp member upon the sup porting base "I of the panel or which may be extended and formed in such a manner as to provide a screw engaging means. As seen in Figure 3, flanged plate 403a may be screwed to the panel and may be formed to encase foot or lug "I to secure the same to the panel.

The foot 402 may be provided at the opposite end of the circuit breaker in order to provide the proper support for a screw I which may be passed therethrough into the panel board supporting member I and secured in any suitable manner as for instance by the nut I.

In order to insure that the circuit breaker will be perfectly level upon the panel board support I, the foot 2 may be flush with the undersurface of the circuit breaker or, ifthis is not feasible, then an additional support 5 may be provided for the purpose. The common bus may, if desired, be protected by any suitable circuit breaker. The circuit to any individual mechanism connected to any one of the circuit breakers will thus be through the common bus 322 to the connecting lead 45 through the circuit breaker and the opposite lead 30 (Figure 4) and therefrom to the load wire 399 (Figure 3) to the mech anism, and then any suitable return, as for instance to the terminal block 423 to which is connected the return wires from the individual loads; the terminal block 420 being connected to the side of the line opposite that to which the common bus is connected.

Each of the individual circuits operated from each of the individual circuit breakers is thus fully protected by its own individual circuit breakers while the entire panel board and all of the elements operated therefrom may, if desired, be protected by a single circuit breaker capable of handling the full load. The panel board itself, as is seen in Figures 2 and 3, comprises a main base or mounting portion 0 upon which the panel board supporting member I is secured in any suitable manner. The main base [and mounting portion 0 may have side members 4H and covering flanges H2. The covering flanges 2 may be formed in order to support a slotted frame covering member 3 which will conceal all of the circuit breakers except for the top surfaces thereof at Ill, 4 from which the finger grasping portion 60 of the manual operating lever 23 projects.

In this manner no part of the circuit breakers or of the panel board or of the connecting wires are accessible except for the manual operating lever above mentioned and except for the indicating means previously described. If desired, also a suitable cover may be mounted upon the flanges 2 to cover over the entire panel board against unauthorized operation thereof. Where the circuit breakers are thus to be mounted closely adjacent to each other, the ends of rivet 22 may be countersunk in the molding (and bosses placed thereabout) to provide an air space between said rivet ends so that they will not be in contact with similar rivet ends on adjacent breakers. The rivet ends on adjacent breakers may then extend slightly into the counterbore. Such adjacent rivet ends are the ones extending from the cover plate. The cover plate is a die 21 cut blank and the head of the rivet engages the cover plate at the rivet openings, while the opposite ends of the rivets in the counterbores or recesses of the molding are spun down.

Where only a thermal trip is desired without changing the structure of the device, then the core of the solenoid coil may be removed or member 245 of the core may be removed, thus leaving a dummy solenoid bushing and coil; in such case, only the thermal trip will operate. In this case also, the coil arrangement may be dispensed with, and the braid 36 from the thermal element may be connected to a metallic tube or other pivotable element which may carry the movable contact arm. Such tube or pivotable element may rotate about an insulating tube similar to the insulating tube 2: of the solenoid.

The present circuit breaker comprises a magnetic trip and a thermal time delay element may be incorporated in the usual form of power and light panel to handle branch circuits. The members, as has been noted, are readily mounted in any suitable support upon the panel and require no more space than a fused switch, and, taking into consideration the expense of replacement of fuses and the expense of operation of the fused switch, they are better than an adequate sub stitute therefor.

They are designed to be mounted in a panel with a number of units side by side with the line terminal of each circuit breaker screwed directly to the common bus, this screw also serving to hold one end of the unit mechanically, the opposite end of the circuit breaker being mechanically supported in any suitable manner. In this manner therefore any individual units may be removed and replaced without disturbing adjoining units.

As has been above noted, the circuit breaker of the present invention is trip free in that it will openeven though the handle is held in closed position and the switch cannot be held against overload or short circuit. The only way in which the circuit breaker may be reset after the interposer has been tripped is by moving the manually interposable interposer between contacts and thus maintaining the contacts in open circuit position. Should the circuit protected by the circuit breaker still be under overload conditions, then permitting the manually interposable interposer to be moved away from between the contacts will again cause the actuation of the thermal and/or solenoid elements to cause the automatically interposable interposer to move between the contacts and thus maintain the separation therebetween.

The circuit breaker, as has been noted, trips immediately upon an excessive overload owing to the operation of solenoid means above described. The thermal tripping means which acts in response to an overload which is not greatly excessive, but nevertheless is excessive, is slowly heated as this minor overload continues until it effects the tripping operation above described. As the overload increases the thermal element acts more and more rapidly. However, should excessive overloads occur, then it may be dangerous to allow any delay until the thermal element is sufficiently heated to accomplish the protecting circuit breaker from tripping upon the occurrence of an excessive overload in a single branch circuit, and thus will serve to prevent the other branch circuits operating from the same bus from being disconnected from the main circuit.

In the foregoing description, cooperating elements have been set forth and the interrelation therebetween has been dscribed.

Various modifications and changes in the different parts will now be obvious to those skilled in the art. Accordingly, it is desired to be bound not by the specific disclosures herein but only by the appended claims.

This case is a division of my parent application Serial No. 331,984, filed April 2'1, 1940. 1. In a circuit interrupter, a support comprising a housing open on each side, a fixed contact and a movable contact, and means for separating said contact, a thermal element for initiating the operation of said contact separating means, said thermal element being mounted in spaced relation to a means for initiating the operation of said contact separating means, said thermal element comprising a bi-metallic strip; a lug on said support, a resilient metallic member supported at said lug, said metallic member carrying said thermal element, and an adjustment for changing the spacing between said thermal element and said means for initiating the operation of said contact separating means comprising a screw and a threaded opening in said metallic member, said screw being engaged in said threaded opening, the end of said screw pressing against said lug, rotation of said screw changing the position of said metallic member and said thermal element with respect to said lug, and said means for initiating the operation of said contact separating means; and a flat cover for said housing maintaining the elements of the circuit interrupter in position in the housing.

2. A circuit interrupter; a molded housing therefor having a side wall, top, bottom and end walls; and an open side wall; said circuit interrupter comprisin a stationary contact, a terminal connected thereto; a movable contact; a latch member operable to initiate the separation of said stationary and movable contacts; and current responsive means for operating said latch member; means in said housing for removably supporting all of said elements; said elements being insertable into coacting engagement with said supporting means through said open side by a movement of said elements in a straight line normal to said open side, and a flat cover for said open side; opposite surfaces of said cover being substantially plane; said cover when in place maintaining said elements in position.

FRANK J. POKORNY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,670,922 Anderson May 22, 1928 2,279,737 Jennings Apr. 14, 1942 1,494,221 De Reamer May 13, 1924 2,303,959 Scott, Jr. Dec. 1, 1942 2,319,262 Pokorny -1 May 18, 1943 2,321,603 Jensen June 15, 1943 

